Several 1D fans tried to sneak past security while the boys were in the gym — and one persistent admirer got an eyeful!

Liam, 18, was seen in the buff by one persistent female fan, British newspaper Metro reports. The band was recently working out at the gym on tour when one young girl snuck past security — and got more than she bargained for!

“Liam was stunned when he saw her in the changing room — he couldn’t believe she’d got past security,” a source told the paper. “For one thing, he was in the middle of getting dressed and had no idea what she was going to do, as their fans in the US are mad.”